More

Stanford Medicine 25 Blog

Reflex Exam (Deep Tendon Reflexes)

The reflex exam is fundamental to the neurological exam and important to locating upper versus lower motor neuron lesions. There are five deep tendon reflexes and a number of superficial and visceral reflexes covered here.

share

Introduction to the Reflex Exam

Reflexes are useful for the general internist to perform, but you can’t evaluate them if…

You don’t have a hammer.

You don’t use proper technique, in which case the reflex will appear to be absent when it is present.

Significant if asymmetric–usually signifies a UMN lesion on the absent side.

Cremaster reflex

Contraction of cremaster muscle (that will pull up the scrotum/testis) after stroking the same side of superior/inner thigh

Absent with:

testicular torsion

upper/lower motor neuron lesions

L1/L2 spinal cord injury

ilioinguinal nerve injury (during hernia repair)

Plantar reflex

The plantar reflex can be:

Normal (Toes down-going)

Absent

Abnormal or "Babinski Present"

Note: It is incorrect to say ‘negative Babinski'

Visceral Reflexes

Anal reflex (anal wink)

Reflexive contraction of the external anal sphincter upon stroking the skin around the anus (afferent: pudendal nerve; efferent: S2-S4)

Bulbocavernosus reflex

Anal sphincter contraction in response to squeezing the glans penis or tugging on an indwelling Foley catheter

Reflex mediated by S2-4 and used in patients with spinal cord injury

DTR Scale

We are not big believers in grading reflexes (grading muscle power is much more useful). Nevertheless, if you need something beyond “absent,” “present,” “brisk,” or “hyperactive” then use below. If you have a hyperactive reflex don’t forget to look for clonus.